Maintaining vegetation along our highways

We design, construct and maintain our roadside areas to keep Washington highways safe and beautiful and to reduce maintenance costs.

Roadside design and construction

The process of keeping the greenery around our highways healthy and safe begins during the design and construction of a new or existing roadway. For information on how WSDOT design and builds roadsides see Roadside and site development. Construction activities sometimes disturb the plants and soils around the worksite. Once construction wraps up, improving the soil and choosing an appropriate plant mix for the roadside take priority.

Ongoing maintenance of roadside vegetation

Our crews take care of the vegetation along the roadside to help travelers see signs, traffic and wildlife. Crews work to remove potentially hazardous trees, control non-native species and establish desirable native plant communities.

Using native plants reduces maintenance and herbicide costs. These species are well-suited to weather and soil conditions, and can grow without constant care. Adding to the natural beauty already found in Washington also controls weeds, which have consequences for farming and native ecosystems, especially pollinators.

An integrated roadside vegetation management plan (IRVM) is a "how to" guide for the best way to manage roadsides in a particular area of the state. Different plans, which include methods and timing, take into account the variety of climates and land uses throughout Washington.

Our vegetation maintenance activities include:

Our maintenance crews use integrated roadside vegetation management (IRVM) plans to apply the right tools, techniques and timing to care for the soil and greenery alongside highways. We update our training programs yearly with successes and lessons learned and we welcome public input.

Learn how we promote the health of our pollinators when managing our roadsides.

We selectively and carefully use herbicides along our roadway and at the edge of water to minimize the risk to human health and the environment. This site includes our toxicology fact sheets for each herbicide used.

Traffic fatality crashes on Washington public roadways

increased 56% in March 2021 compared to March 2020.

11,906 incidents responded to

by WSDOT’s incident Response teams during the third quarter of 2021, nearly 6% more than same quarter in 2020.

WSF ridership was nearly 5.7 million in the first quarter of fiscal year 2022,

which was 1.6 million (38.3%) higher than the corresponding quarter in FY2021